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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 | /* SPDX-License-Identifier: GPL-2.0 */ /* * A security identifier table (sidtab) is a lookup table * of security context structures indexed by SID value. * * Original author: Stephen Smalley, <sds@tycho.nsa.gov> * Author: Ondrej Mosnacek, <omosnacek@gmail.com> * * Copyright (C) 2018 Red Hat, Inc. */ #ifndef _SS_SIDTAB_H_ #define _SS_SIDTAB_H_ #include <linux/spinlock_types.h> #include <linux/log2.h> #include <linux/hashtable.h> #include "context.h" struct sidtab_entry { u32 sid; u32 hash; struct context context; #if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0 struct sidtab_str_cache __rcu *cache; #endif struct hlist_node list; }; union sidtab_entry_inner { struct sidtab_node_inner *ptr_inner; struct sidtab_node_leaf *ptr_leaf; }; /* align node size to page boundary */ #define SIDTAB_NODE_ALLOC_SHIFT PAGE_SHIFT #define SIDTAB_NODE_ALLOC_SIZE PAGE_SIZE #define size_to_shift(size) ((size) == 1 ? 1 : (const_ilog2((size) - 1) + 1)) #define SIDTAB_INNER_SHIFT \ (SIDTAB_NODE_ALLOC_SHIFT - size_to_shift(sizeof(union sidtab_entry_inner))) #define SIDTAB_INNER_ENTRIES ((size_t)1 << SIDTAB_INNER_SHIFT) #define SIDTAB_LEAF_ENTRIES \ (SIDTAB_NODE_ALLOC_SIZE / sizeof(struct sidtab_entry)) #define SIDTAB_MAX_BITS 32 #define SIDTAB_MAX U32_MAX /* ensure enough tree levels for SIDTAB_MAX entries */ #define SIDTAB_MAX_LEVEL \ DIV_ROUND_UP(SIDTAB_MAX_BITS - size_to_shift(SIDTAB_LEAF_ENTRIES), \ SIDTAB_INNER_SHIFT) struct sidtab_node_leaf { struct sidtab_entry entries[SIDTAB_LEAF_ENTRIES]; }; struct sidtab_node_inner { union sidtab_entry_inner entries[SIDTAB_INNER_ENTRIES]; }; struct sidtab_isid_entry { int set; struct sidtab_entry entry; }; struct sidtab_convert_params { int (*func)(struct context *oldc, struct context *newc, void *args); void *args; struct sidtab *target; }; #define SIDTAB_HASH_BITS CONFIG_SECURITY_SELINUX_SIDTAB_HASH_BITS #define SIDTAB_HASH_BUCKETS (1 << SIDTAB_HASH_BITS) struct sidtab { /* * lock-free read access only for as many items as a prior read of * 'count' */ union sidtab_entry_inner roots[SIDTAB_MAX_LEVEL + 1]; /* * access atomically via {READ|WRITE}_ONCE(); only increment under * spinlock */ u32 count; /* access only under spinlock */ struct sidtab_convert_params *convert; spinlock_t lock; #if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0 /* SID -> context string cache */ u32 cache_free_slots; struct list_head cache_lru_list; spinlock_t cache_lock; #endif /* index == SID - 1 (no entry for SECSID_NULL) */ struct sidtab_isid_entry isids[SECINITSID_NUM]; /* Hash table for fast reverse context-to-sid lookups. */ DECLARE_HASHTABLE(context_to_sid, SIDTAB_HASH_BITS); }; int sidtab_init(struct sidtab *s); int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context); struct sidtab_entry *sidtab_search_entry(struct sidtab *s, u32 sid); struct sidtab_entry *sidtab_search_entry_force(struct sidtab *s, u32 sid); static inline struct context *sidtab_search(struct sidtab *s, u32 sid) { struct sidtab_entry *entry = sidtab_search_entry(s, sid); return entry ? &entry->context : NULL; } static inline struct context *sidtab_search_force(struct sidtab *s, u32 sid) { struct sidtab_entry *entry = sidtab_search_entry_force(s, sid); return entry ? &entry->context : NULL; } int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params); void sidtab_cancel_convert(struct sidtab *s); int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid); void sidtab_destroy(struct sidtab *s); int sidtab_hash_stats(struct sidtab *sidtab, char *page); #if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0 void sidtab_sid2str_put(struct sidtab *s, struct sidtab_entry *entry, const char *str, u32 str_len); int sidtab_sid2str_get(struct sidtab *s, struct sidtab_entry *entry, char **out, u32 *out_len); #else static inline void sidtab_sid2str_put(struct sidtab *s, struct sidtab_entry *entry, const char *str, u32 str_len) { } static inline int sidtab_sid2str_get(struct sidtab *s, struct sidtab_entry *entry, char **out, u32 *out_len) { return -ENOENT; } #endif /* CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0 */ #endif /* _SS_SIDTAB_H_ */ |